<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>


  <body>
    <%
        String str = request.getParameter("number");
        int n = Integer.parseInt(str);
        int sum=0;
        for(int i=0;i<n;i++)
        {
        	sum+=i;
        }
    %>
    <p>
                 从1到<%=n %>的累加和是:
    <br>
      <%=sum %>
    </body>
 </html>
